TECHNICAL FIELD
[0001] The present disclosure relates to dust extraction devices for use with construction
equipment. There are disclosed hatches for dumping dust accumulated in a pre-separator
such as a cyclone device into a dust container. There are also disclosed various dust
containers for use together with the hatches.
BACKGROUND
[0002] Dust and slurry are created by cutting, drilling, grinding and/or demolishing concrete,
brick, and other hard construction materials. The dust and slurry may be collected
by a dust extractor and removed from the construction site in a controlled manner.
Dust extractors collect the dust and slurry by generating a vacuum by means of an
impeller and motor arrangement, i.e., similar to a vacuum cleaner for domestic use.
Many industrial grade dust extractors comprise a pre-separator or cyclone device followed
by an essential filter such as a high-efficiency particulate air (HEPA) filter.
[0003] During operation, dust gradually accumulates inside the pre-separator chamber and
needs to be emptied regularly into a dust container such as a disposable bag or other
type of dust container. One example of a disposable dust container is the Longopac
® bagging system discussed, e.g., in
US 2018/0192838.
[0004] A hatch mechanism separates the pre-separator chamber from the dust container. Several
hatch mechanisms are known, such as hinged metal hatches, but such hatches have been
known to damage and even puncture dust container bags and may not always be able to
efficiently empty accumulated dust and slurry into the dust container.
WO 2017/171596 discusses a type of hatch mechanism based on an aperture with a grid or net in combination
with a hose device made of a flexible material. This hatch mechanism is less likely
to damage dust container bags.
[0005] Rigid buckets may also be used to collect the dust and slurry from the dust extraction
operation. It is of course desirable that the dust container is easily fitted to the
dust extractor, and that both dust collection and disposal of collected dust and slurry
is convenient for the operator to perform.
[0006] Some forms of dust, such as fine concrete dust, tends to clot and lump when accumulated
at the bottom of the pre-separator. It may be difficult to efficiently empty such
accumulated dust from the pre-separator. The design proposed in
WO 2017/171596 may not always provide optimal emptying performance. Thus, there is a need for improved
pre-separator hatch mechanisms for industrial grade dust extractors.
[0007] The pre-separator or cyclone normally comprises an air filter which gradually becomes
particle-laden, i.e., clogged, during operation. This filter therefore needs to be
cleaned regularly. It is known to clean the air filter in the pre-separator by means
of a relief valve to generate a reverse thrust of air, or air pulse, as discussed
in, e.g.,
WO 2017/171596,
WO 2017/025305, and
EP3619453. However, the design of a relief valve which generates this reverse thrust of air
is not straight forward. There is a need for improved valve arrangements for generating
such pulses of air which allow efficient filter cleaning in a convenient manner.
SUMMARY
[0008] It is an object of the present disclosure to provide improved dust extraction devices.
This object is obtained by a protective shroud according to claim 1.
[0009] Other aspects of the disclosure relate to a hatch mechanisms for use with industrial
grade dust extractors which alleviate at least some of the above-mentioned issues.
[0010] According to aspects a hatch mechanism for a pre-separator or filter tank is provided.
The mechanism comprises an aperture having a perimeter, and at least three elongated
obturator elements pivotably attached along the perimeter at respective hinge ends.
Each obturator element has a distal end arranged opposite to the hinge end along the
extension direction of the obturator element. Adjacent obturator elements arranged
along the perimeter are connected by foldable joining members arranged to guide the
distal ends to a common intersection point. This common intersection point is distanced
from a plane of the aperture, whereby the obturator elements are arranged to fold
about respective hinge ends to a position of mutual support to close the hatch mechanism.
[0011] This hatch mechanism is lenient to a dust container bag, i.e., is not likely to puncture
or otherwise damage a dust container bag. At the same time the hatch mechanism opens
up to present a wide area aperture between the pre-separator main chamber where the
dust accumulates and the dust container bag. This simplifies emptying dust and slurry
from the pre-separator into the dust container. The hatch mechanism is, by the foldable
jointing member, not a rigid structure, but will move slightly during dust extraction
operation due to pressure differences over time on the pre-separator main chamber.
This movement will prevent dust from forming into semi-solid lumps which are more
difficult to empty into the dust container. The hatch mechanism is also applicable
together with other dust extractor tanks.
[0012] According to aspects, the aperture has a circular or an elliptical shape, or a polygonal
shape with number of equal sized faces equal to the number of obturator elements.
These aperture geometries allow for presenting a large area aperture for emptying
dust and slurry.
[0013] According to aspects, six obturator elements are arranged evenly spaced along the
perimeter of the aperture. This geometry has been found particularly suitable for
the present purpose of providing an efficient hatch mechanism which allows convenient
emptying of dust and slurry into the dust container.
[0014] According to aspects, an obturator element comprises a rigid or semi-rigid batten
structure. These battens can be integrally formed or otherwise attached to the foldable
joining member structures, which is an advantage. The battens can be formed in a cost-effective
manner from, e.g., metal, or plastic bars.
[0015] According to aspects, the obturator elements are pivotably attached via a resilient
portion at the hinge end of each obturator element. This way a cost-efficient yet
durable hinge function is provided. The resilient portion hinges are also non-rigid,
thereby promoting motion of the hinge mechanism during use of the dust extractor as
discussed above.
[0016] According to aspects, the foldable joining members are integrally formed as a tubular
element in a resilient material, to which tubular element the obturator elements are
attached. This tubular element can be manufactured in a cost-effective manner.
[0017] According to aspects, the perimeter comprises a rim portion with first and second
flanges extending radially outwards from the rim portion with an axial separation.
The first flange and the second flange are configured to mate with a flange portion
on a dust container holder extending radially inwards to mate with the first and second
flanges. This way a dust container holder can be fitted onto the hatch structure in
a convenient and robust manner. This voids the need for separate holding structures
for attaching the dust container holder, which is an advantage.
[0018] There is also disclosed herein a dust container holder suitable for mating with a
hatch mechanism. The dust container holder comprises a tubular body extending between
first and second end perimeters. A flange portion extends radially inwards in connection
to the first end perimeter. A groove portion extends radially outwards in connection
to the second end perimeter. This groove portion is configured to hold a dust container.
[0019] A dust container holder is a device arranged to hold a store of disposable or re-usable
dust containers, such as a plastic bag dust container system like the Longopac
® bagging system discussed above. Dust containers are fitted in the dust container
holder and the combination of dust containers and dust container holder can be mounted
onto the hatch mechanism. This dust container holder can be releasably fitted onto
the hatch mechanism in a convenient manner. A dust container bag system like the Longopac
® bagging system can be placed in the groove portion and the dust container holder
fitted onto the hatch mechanism. When the dust container bag system is depleted, the
dust container holder can be conveniently removed, and a new dust container bag system
fitted into the groove portion.
[0020] The dust container holders discussed herein are particularly suitable for use together
with the hatch mechanism. However, it is appreciated that the dust container holders
may also be used with other forms of pre-separator designs. For instance, a pre-separator
may lack the hatch mechanism discussed herein, but still comprise means arranged,
e.g., on the pre-separator tank, for holding the flange portion of the dust container
holder.
[0021] According to aspects, the dust container holder is arranged to be fitted onto the
hatch mechanism by pushing the first end perimeter over the hatch mechanism. The flange
portion is configured to hold the dust container in position between the flange portion
and the hatch mechanism. Thus, there is no need for holding straps or the like, which
is an advantage.
[0022] Other aspects of the disclosure relate to providing an improved pre-separator filter
cleaning arrangement which alleviate at least some of the above-mentioned issues.
[0023] According to aspects a valve arrangement for generating a pulse of air to clean an
air filter of a pre-separator is provided. The arrangement comprises a main valve
closure body arranged to seal a passage between a high pressure side and a low pressure
side of the valve arrangement, a control body connected to the main valve closure
body, such that a position of the main valve closure body is determined by a position
of the control body, a control chamber partially defined by the control body, whereby
a volume of the control chamber is variable in relation to the position of the control
body, and a control chamber valve having an open state and a closed state for regulating
a pressure in the control chamber. The valve arrangement further comprises a resilient
trigger membrane arranged between the high pressure side and the low pressure side
such that a position of the resilient trigger membrane is dependent on a pressure
difference between the high pressure side and the low pressure side, wherein the state
of the control chamber valve is determined by the position of the resilient trigger
membrane such that the control chamber valve is in the open state when the pressure
difference is above a threshold and in the closed state otherwise.
[0024] This mechanism provides an automatically triggered air pulse for cleaning an air
filter, thus avoiding the need for an operator to manually trigger filter cleaning.
The mechanism is mechanical in nature, voiding the need for complicated control units
and sensor arrangements, which is an advantage.
[0025] According to aspects, a lever is arranged pivotable about an axis and arranged to
connect the resilient trigger membrane to the control chamber valve. This lever provides
leverage which can be tuned to the force requirements of the application at hand,
which is an advantage. The lever also distances the trigger membrane from the control
chamber, thereby simplifying functional layout of the design an providing a valve
arrangement with reduced footprint, which is an advantage.
[0026] According to aspects, the valve arrangement further comprises a calibration device
configured to determine the threshold by biasing the lever to resist pivoting about
the axis. This calibration device can be used in-field to adjust the automatic triggering
function of the valve arrangement.
[0027] According to aspects, the lever is operable by a manual control device to force the
control chamber valve into the open state. Thus, the automatic triggering function
can be overridden in a convenient manner.
[0028] According to aspects, the control chamber valve and the resilient trigger membrane
are integrally formed. This further reduces footprint and provides a compact design,
which is an advantage.
[0029] There are also disclosed herein pre-separators and dust extractors associated with
the above-mentioned advantages.
[0030] Generally, all terms used in the claims are to be interpreted according to their
ordinary meaning in the technical field, unless explicitly defined otherwise herein.
All references to "a/an/the element, apparatus, component, means, step, etc." are
to be interpreted openly as referring to at least one instance of the element, apparatus,
component, means, step, etc., unless explicitly stated otherwise. The steps of any
method or process disclosed herein do not have to be performed in the exact order
disclosed, unless explicitly stated. Further features of, and advantages with, the
present invention will become apparent when studying the appended claims and the following
description. The skilled person realizes that different features of the present invention
may be combined to create embodiments other than those described in the following,
without departing from the scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The present disclosure will now be described in more detail with reference to the
appended drawings, where
Figures 1A-B show an example dust extractor;
Figures 2A-C schematically illustrate a hatch mechanism;
Figure 3 schematically illustrates a hatch mechanism in closed position;
Figures 4A-C illustrate an example hatch mechanism in closed position;
Figures 5A-C illustrate an example hatch mechanism in open position;
Figure 6 illustrates an example dust container holder arrangement;
Figure 7A-B shows a dust container holder attached to a hatch mechanism;
Figure 8 schematically illustrates a dust container holder arrangement;
Figures 9A-B illustrates an example dust extractor lid portion;
Figures 10A-C show example valve arrangements for generating pulses of air;
Figure 10D schematically illustrates a principle of a triggering membrane;
Figures 11A-C conceptually illustrate the generation of an air pulse;
Figures 12A-C show an example dust container system;
Figures 13A-B show details of a dust container holder;
Figure 14 is an exploded view of a hatch mechanism with a support element;
Figure 15 shows details of a hatch mechanism with a support element;
Figures 16A-B illustrate an example protective shroud arrangement; and
Figure 17 shows views of an example protective shroud arrangement.
DETAILED DESCRIPTION
[0032] The invention will now be described more fully hereinafter with reference to the
accompanying drawings, in which certain aspects of the invention are shown. This invention
may, however, be embodied in many different forms and should not be construed as limited
to the embodiments and aspects set forth herein; rather, these embodiments are provided
by way of example so that this disclosure will be thorough and complete, and will
fully convey the scope of the invention to those skilled in the art. Like numbers
refer to like elements throughout the description.
[0033] It is to be understood that the present invention is not limited to the embodiments
described herein and illustrated in the drawings; rather, the skilled person will
recognize that many changes and modifications may be made within the scope of the
appended claims.
[0034] Figures 1A and 1B show an example dust extraction device 100. The dust extraction
device can be connected via a hose to a dust generator (not shown in Figure 1), such
as a core drill, a floor grinder, a concrete saw, or the like. The dust and slurry
from the dust generator enters the dust extractor via an inlet 110. A pre-separator
120 is arranged after the inlet, i.e., downstream with respect to the airflow direction
into the inlet 110. The pre-separator may comprise a cyclone with a pre-filter for
separating out larger debris particles from the particle-laden airflow entering the
inlet 110. The larger debris particles may be collected via an outlet 130 of the pre-separator
120. A hatch mechanism 140 is arranged to close the outlet 130 during operation. Figure
1A also shows a dust extractor lid 101 which forms an upper portion of the dust extractor
100. The lid 101 is not shown in Figure 1B.
[0035] Generally, herein, an upwards direction on the dust extractor is indicated by arrow
U, and a downwards direction opposite to the upwards direction is indicated by arrow
D. The upwards direction points away from the ground support part of the dust extractor,
i.e., away from the ground when the dust extractor is in use.
[0036] The dust extractor 100 may of course also be used together with a regular vacuum
cleaner nozzle.
[0037] The dust extractor 100 may be powered from electrical mains via cable, or by one
or more batteries.
[0038] The pre-separator 120 may also be referred to as a cyclone, a cyclone tank, or a
filter tank. As noted above, the hatch mechanisms discussed herein are applicable
with most dust extractors for industrial use and need not be arranged to seal a pre-separator.
Rather, the hatch mechanisms can be used to seal any filter tank structure.
[0039] The air flow continues from the pre-separator 120 via one or more conduits in the
lid 101 into one or more essential filters 150, here shown inside a filter holder
155. An essential filter is a filter designed to meet strict requirements on filtering
function. Such an essential filter 150 may, e.g., be a High-Efficiency Particulate
Air (HEPA) filter, but other air filters may also be used.
[0040] A blower arrangement 160 is arranged downstream from the pre-separator 120 and from
the one or more essential filters 150. The blower arrangement generates a suction
force or vacuum which draws the particle-laden airflow in through the inlet 110, past
the pre-separator 120, and through the one or more essential filters 150. Herein,
a vacuum or vacuum level indicates how far below a reference pressure level, such
as atmospheric pressure, the pressure in the airflow is.
[0041] The dust extractor 100 may also comprise a control unit 170 configured to perform
various control actions, such as monitoring pressure levels at various places in the
dust extractor 100 and controlling the blower arrangement 160.
[0042] The hatch mechanism 140 is an important part of the dust extractor 100. This hatch
is used when emptying the pre-separator chamber into a dust container which is arranged
below the hatch (but not shown in Figures 1A-B). The dust container may, e.g., be
a removable box structure, a bucket, or a plastic bag, such as the Longopac
® bagging system mentioned above. If the hatch mechanism is used with a non-rigid plastic
bag dust container system, it is important that the dust bag is not sucked into the
pre-separator chamber via the hatch. However, this does not mean that the hatch needs
to be air-tight during operation.
[0043] The present disclosure relates to hatch mechanisms which close to prevent the dust
container from being sucked into the pre-separator during operation, while at the
same time allowing for easy emptying of dust into the dust container. The hatch mechanisms
are designed so as to not damage a plastic bag dust container.
[0044] Aspects of the present disclosure also relate to hatch mechanisms that comprise a
universal attachment interface for attaching various types of dust containers. Thus,
the same type of attachment mechanism is used regardless of whether a single plastic
bag, a bagging system like the Longopac system, or a rigid bucket is used. This way
an operator can choose an appropriate dust container for the task at hand, without
modifying the dust extractor, or the hatch mechanism.
[0045] Figures 2A-C schematically illustrate a hatch mechanism according to the present
disclosure. The hatch mechanisms 140 discussed herein are generally suitable for use
with pre-separators 120, such as the pre-separator exemplified in Figures 1A and 1B.
[0046] The mechanism comprises an aperture 210 having a perimeter 220 arranged in a plane
230. It is via this aperture that the accumulated dust and slurry is dumped into the
dust container below the hatch mechanism. To empty the pre-separator chamber, the
low operating pressure inside the chamber is first increased, e.g., by opening a conduit
to outside atmosphere as during filter cleaning, or by turning off the blower arrangement
160. The plane 230 can be defined freely to be some plane having the main emptying
direction of the hatch as its normal. It is appreciated that the perimeter need not
be perfectly aligned with the plane along the entire circumference.
[0047] At least three elongated obturator elements 240 are pivotably attached 250 along
the perimeter 220 at respective hinge ends 241. Each obturator element comprises a
distal end 242 arranged opposite to the hinge end along the extension direction of
the obturator element 240. This means that each obturator element is connected to
the perimeter 220 in a way such that it can swing inwards with respect to the aperture.
[0048] Figure 3 shows an example hatch mechanism 140 in closed position where the pivoting
motion 250 by the obturator elements 240 has been indicated. Adjacent obturator elements
240 arranged along the perimeter 220 are connected by foldable joining members 260
arranged to guide the distal ends 242 to a common intersection point 270 distanced
d from the plane 230, whereby the obturator elements 240 are arranged to fold about
respective hinge ends 241 to a position of mutual support to close the hatch mechanism
140. Thus, the obturator elements swing inwards to a position of mutual support, forming
an upside-down cone- or pyramid-like structure where the distal ends meet at the pointy
end. An obturator element 240 may, e.g., be realized by a rigid or semi-rigid batten
structure, such as a metal bar structure or an elongated plastic structure.
[0049] When this structure is subject to a pressure gradient over the aperture, the obturator
elements 240 and foldable joining members 260 will be sucked towards the pre-separator
chamber, i.e., in direction of the aperture 210. This will cause the obturator elements
240 to pivot as illustrated in Figure 3 which closes the hatch, at least sufficiently
in order for a dust container bag to not get sucked into the pre-separator chamber.
When the low pressure in the pre-separator chamber is released, the obturator elements
240 will no longer be held in closed position, but will swing radially outwards, thereby
opening the hatch. According to some aspects the obturator elements 240 are configured
with an increased weight in order to promote opening of the hatch by gravitational
force.
[0050] In some cases, an optional annular structural support member 1410 may be used to
provide a stop such that the obturator elements 240 cannot pivot past the position
of mutual support. This annular structural support member will be discussed in more
detail below in connection to Figure 14.
[0051] The hatch mechanisms proposed herein are not rigid like other known hatch mechanism
based on metal lids and the like. Rather, the hatch can be integrally formed in a
resilient material which moves and/or vibrates during operation, such as during smaller
pressure differences over time in the pre-separator main chamber. This motion by the
hatch mechanism prevents dust and slurry from forming more solid lumps which are difficult
to empty. Also, the hatch mechanism may even allow dust and slurry to penetrate the
hatch mechanism despite a pressure gradient over the aperture when the accumulated
dust obtains sufficient weight to overcome the suction force which closes the hatch.
This means that the hatch mechanisms disclosed herein may automatically open as needed
to dump dust and slurry into the dust container below the hatch. This automatic opening
may, e.g., take place when the air filter 125 is cleaned by a reverse thrust of air.
[0052] Figures 4A-C illustrate an example hatch mechanism in closed position. Figures 5A-C
illustrate the same example hatch mechanism in open position.
[0053] In this example the aperture 210 has a circular shape and the common intersection
point 270 is located at the center of the aperture. However, other shapes are also
possible. For instance, an elliptical aperture shape could be used, where the obturator
members 240 are of different length in order to fold about the respective hinge ends
241 to a position of mutual support to close the hatch mechanism 140.
[0054] According to some other aspects, the aperture 210 has a polygonal shape with number
of equal sized faces equal to the number of obturator elements 240.
[0055] The common intersection point 270 can be located anywhere in the aperture, e.g.,
offset to one side, as long as the common intersection point 270 is distanced d from
the plane 230. The obturator elements 240 are then matched to meet at the common intersection
point when pivoting about the hinge ends 241.
[0056] In the example shown in Figures 4A-C and 5A-C, six obturator elements 240 are arranged
evenly spaced along the perimeter 220 of the aperture 210. The obturator elements
240 are pivotably attached via a resilient portion at the hinge end 241 of each obturator
element 240, i.e., a rubber or soft plastic part separating the obturator member from
the perimeter to allow pivoting by the obturator member. Each obturator element is
configured with a distal end 242 with a polygon shape matched to adjacent obturator
elements. In this case the polygon shape has two opposing tangential sides 243 arranged
at an acute angle of about 60 degrees in order to interface with adjacent obturator
elements, and two radial sides 244 as indicated in Figure 4C.
[0057] According to another example, the obturator elements 240 are pivotably attached via
a hinge at the hinge end 241 of each obturator element 240. This hinge may, e.g.,
be a piano hinge or the like.
[0058] The foldable joining members 260 are preferably but not necessarily made of a flexible
sheet material. As an alternative to using a flexible sheet material like rubber,
hinges can also be used to allow folding. The important feature here is that the folding
members guide to obturator elements to the position of mutual support during pivoting
about the respective hinge ends.
[0059] In the example shown in Figures 4A-C and 5A-C, the foldable joining members 260 are
arranged with a folding indication configured extending along a line from a point
on the perimeter halfway between the adjacent obturator elements towards a geometric
center of the aperture 210. Preferably, the foldable joining members 260 are integrally
formed as a tubular element in a resilient material, such as rubber, i.e., a flexible
structure resembling a hose or other resilient cylindrical structure, to which tubular
element the obturator elements 240 are attached. The obturator elements 240 can also
be molded into or otherwise integrally formed with the tubular structure. It may as
mentioned above be advantageous to arrange the obturator elements with a relatively
large weight, where the weight is configured in dependence of the power of the dust
extractor, in order to promote opening of the hatch mechanism during emptying of dust
and slurry into the dust container.
[0060] Figure 14 and Figure 15 illustrate an optional annular structural support member
1410 arranged in connection to the perimeter 220 of the hatch mechanism 140, on the
side facing the pre-separator 120. The annular structural support member extends transversally
to the elongated obturator elements 240 and prevents pivoting by the elongated obturator
elements 240 beyond the position of mutual support, as shown in Figure 3. Thus, as
the obturator elements are exposed to suction force by the dust extractor which biases
the obturator elements towards the position of mutual support, the annular structural
support member acts as a stop which prevents the obturator elements from pivoting
too far in the radial direction past the position of mutual support.
[0061] The annular structural support member 1410 is arranged to be at least partially enclosed
by the hatch mechanism, i.e., to have a position radially interior to the hatch mechanism,
as shown in Figure 15. The diameter D1 of the rim portion 1430 is therefore smaller
than the largest diameter D2 of the hatch mechanism 140 and smaller than at least
one other diameter of the hatch mechanism. The diameter D1 of the rim portion 1430
may, e.g., be configured to match the internal diameter of the hatch mechanism at
a supporting position.
[0062] The annular structural support member 1410 needs to be rigid enough so as to be able
to hold an obturator element from pivoting too far past the position of mutual support.
It may, e.g., be formed in a rigid sheet metal material or in a rigid plastic material.
The annular member is preferably configured with a frustoconical shape 1440 matched
to the shape of the elongated obturator elements 240 at the respective hinge ends
241, as shown in Figure 15.
[0063] The annular structural support member 1410 can be held in position in-between the
pre-separator 120 and the hatch mechanism 140. For instance, a radially protruding
rim portion 1430 can be arranged on the support member. In this case the annular structural
support member 1410 is arranged to be supported on the hatch mechanism by the radially
protruding rim portion 1430, i.e., the support member is at least in part suspended
on the rim portion resting on the hatch mechanism interior.
[0064] A groove may be formed in a resilient interior portion of the hatch mechanism, which
groove matches the rim portion 1430. The rim portion may enter into the groove, and
consequently be held in position relative to the hatch mechanism.
[0065] The hatch mechanism 140 may, according to some aspects, be attached to the pre-separator
120 by a plurality of rivets 1420, as illustrated in Figure 14. Of course, other fastening
means may also be used, such as bolts or an adhesive. A rim and matching groove arrangement
can also be used, with the advantage that the hatch mechanism becomes more easily
detached from the pre-separator 120and thus more easily serviceable.
[0066] With reference again to Figures 1A and 1B, some dust extractors 100 comprise dust
container holder arrangements 180. Figure 6 illustrates an example of such a dust
container holder arrangement 180. Some of the hatch mechanisms 140 disclosed herein
are configured to hold a dust container arrangement. According to such aspects, with
reference to, e.g., Figure 4B and 5B, the perimeter 220 of the hatch mechanism 140
comprises a rim portion 410 with first 420 and second 430 flanges extending radially
outwards from the rim portion with an axial separation a.
[0067] With reference also to Figure 7A and Figure 7B, the first flange 420 and the second
flange 430 of the hatch mechanism 140 are configured to mate with a flange portion
630 on the dust container holder 180 which extends radially inwards Ri to mate with
the first and second flanges on the hatch mechanism. Figures 7A-B show a dust container
holder 180 attached to a hatch mechanism 140 by these radial flanges.
[0068] To mount the dust container holder 180 onto the dust extractor, an operator simply
pushes the dust container holder 180 onto the hatch mechanism 140, in an upwards direction
U opposite to the downwards direction indicated by arrow D in Figure 7A and 7B. The
flange portion 630 then traverses past the second flange 430 of the hatch mechanism
140 and then catches onto the first flange portion 420 on the hatch mechanism 140.
The dust container holder is then held in position, since the flange portion 630 is
supported in-between the first and second flange portions 420, 430 of the hatch mechanism,
as shown in Figure 7B.
[0069] To remove the dust container holder 180, the operator pulls the dust container holder
180 in the downwards direction D with enough force such that the flange portion 630
overcomes the supporting force exerted by the second flange portion 430. Thus, the
dust container holder is releasably held in position by the first and second flange
portions 420, 430 of the hatch mechanism in cooperation with the flange portion 630
of the dust container holder.
[0070] It is appreciated that one or both of the dust container flange portion 630 and the
second flange portion 430 of the hatch mechanism may be formed in a resilient material
to allow the dust container holder 180 to traverse onto the hatch mechanism 140. One
of the dust container flange portion 630 and the second flange portion 430, but not
both, may be formed in a rigid material, such as plastic or metal.
[0071] An advantage with the attachment arrangement comprising the system of cooperating
flanges 420, 430, 630, is that other types of dust container holders can also be attached
to the same hatch mechanism, thus allowing an operator to select which type of dust
container to use for a given dust extraction task. A holder configured to hold a single-use
industrial plastic bag may, e.g., be configured with the flange portion 630. A rigid
bucket will be discussed below in connection to Figures 12A-C and Figures 13A-B.
[0072] The dust container holder 180 in Figure 6 comprises a tubular body 610 extending
between first 611 and second 612 end perimeters. The flange portion 630 extends radially
inwards Ri in connection to the first end perimeter 611. A groove portion 620 extends
radially outwards Ro in connection to the second end perimeter. This groove portion
620 is configured to hold a dust container 810, such as the Longopac
® bagging system.
[0073] Figure 8 schematically illustrates a dust container assembly 800 comprising a dust
container holder arrangement according to the present teaching fitted onto a hatch
mechanism. Note how the dust container 810 is crimped 820 (like the bellows of an
accordion) and fitted into the groove portion 620, with an end section 840 that is
squeezed between the first flange 420 and the second flange 430 of the hatch mechanism
140, and the flange 630 of the dust container holder 180. The dust container is sealed
by a sealing member 830, such as a zip-tie, cable-tie, a piece of string, or the like.
[0074] It is appreciated that a normal industrial-grade plastic bag may also be fitted to
the dust container holder 180 in this manner, i.e., the dust container holder 180
may be used with other dust container systems, not only with a Longopac bagging system.
[0075] The dust container holder 180 is arranged to be fitted onto the hatch mechanism 140
by pushing the first end perimeter 611 over the hatch mechanism, wherein the flange
portion 630 is configured to hold the dust container 810 in position between the flange
portion and the hatch mechanism 140. This way the dust container can be easily fitted
onto the dust extractor. The dust container is releasably held in position between
the flanges, which voids the need for additional fastening means to hold the dust
container in position.
[0076] Figures 12A-C and Figures 13A-B illustrate an alternative dust container arrangement
1200. Here, the dust container is instead a bucket which is arranged to receive the
dust and slurry output via the hatch mechanism 140. The bucket may then be emptied
and replaced to receive more dust and slurry. The interface between the hatch mechanism
140 and the bucket is the same as that discussed above in connection to, e.g., Figure
7A and Figure 7B, which means that an operator can choose between different dust container
options without further modifications to the dust extractor. Some dust extraction
tasks may be more suitably carried out with a Longopac bagging system, while some
other dust extraction tasks are more suitably executed using a bucket as dust container.
The dust extractor 100 may be sold together with a kit of parts comprising a first
dust container holder configured to hold, e.g., a Longopac bagging system, and a second
dust container holder configured to hold a bucket. In other words, the second end
perimeter 612 of this dust container is a plane which seals the dust container.
[0077] Figures 12A-C and Figures 13A-B show a dust container holder 1210 for mating with
a hatch mechanism 140. The dust container holder again comprises a tubular body 610
extending from a first 611 end perimeter, wherein a flange portion 630, showed in
Figure 13B, extends radially inwards Ri in connection to the first end perimeter 611,
wherein the dust container holder 1210 is closed at an end opposite to the first end
perimeter 611 to form a bucket. The bucket part of the dust container holder 1210
may be integrated with the dust container holder as shown in Figures 12A-C. Alternatively,
the bucket part may be releasably attached to the dust container holder 1210 by, e.g.,
bayonet attachment, or a threaded portion.
[0078] The dust container holder 1210 is arranged to be fitted onto the hatch mechanism
140 by pushing the first end perimeter 611 over the hatch mechanism. The flange portion
630 is configured to hold the dust container 810 in position by entering in-between
the first 420 and second 430 flange portions of the hatch mechanism 140, as shown
in Figure 13B.
[0079] Thus, advantageously, an operator may freely choose between a plurality of dust container
options. Some dust extraction tasks may be better performed with a single durable
plastic bag mounted onto a dust container holder like that shown in Figure 7A and
7B. Other dust extraction tasks may be more conveniently performed by mounting a Longopac
Bagging system to the dust container holder. Finally, a bucket may also be used with
the same dust container holding arrangement. An operator is provided with several
dust container options, and is free to mount whichever dust container that is preferred
using the same mechanical attachment interface, i.e., the flange portion 630, which
extends radially inwards Ri in connection to the first end perimeter 611, which is
the same flange portion that was discussed above in connection to Figures 7A-B.
[0080] The dust container holders discussed herein are particularly suitable for use together
with a hatch mechanism like that illustrated in, e.g., Figure 7A. However, it is appreciated
that the dust container holders may also be used with other forms of pre-separator
designs. For instance, a pre-separator may lack the hatch mechanism discussed herein,
but still comprise means arranged, e.g., on the pre-separator tank, for holding the
flange portion of the dust container holder. For instance, the first and second flanges
420, 430 may be assembled directly onto a pre-separator tank, whereupon the dust container
holder can be used independently from the type of pre-separator design. The dust container
holders may then be used with a simple grating closure, or some other form of closing
lid mechanism.
[0081] During some dust extraction operating scenarios, dust and slurry 855 may find its
way into the creases of the dust container bagging system when received in the groove
portion 620, as indicated in Figure 8 by the dash-dotted line 850. This dust and slurry
may cause inconvenience to an operator, and may also damage the dust container, which
is of course undesired.
[0082] Figures 16 and 17 shows an optional protective shroud 1610 arranged to at least partly
cover the dust container 810 when received in the groove portion 620, as shown in
Figure 16B, where the dust container is only schematically illustrated. The protective
shroud 1610 may be formed in a resilient material allowing the protective shroud to
be folded over a dust container 810 received in the groove portion 620. Thus, an operator
may insert a dust container such as the Longopac
® bagging system discussed above into the groove portion 620, and then fold the protective
shroud 1610 over the dust container, thereby shielding the dust container from dust
and slurry. The protective shroud 1610 may be configured with an outer diameter 1620
larger than an outer diameter of the dust container 810, and with an inner diameter
1630 smaller than an inner diameter of the dust container 810, as shown in Figure
17.
[0083] It is noted that neither of the dust container holder nor the protective shroud depends
on the features of the hatch mechanism. Rather, both the dust container holders discussed
herein as well as the protective shroud may also be used on a dust extractor which
does not comprise the hatch mechanisms of the present disclosure. For instance, a
pre-separator tank may be designed with a separate arrangement comprising flanges
like the first flange portion 420 and the second flange portion 430, to receive and
to hold the dust container holder in position during use.
[0084] The protective shroud 1610 may be arranged to extend over the top section of the
dust container 810 as illustrated in Figure 16B. However, the protective shroud 1610
may also be configured to extend downwards in direction D to shield the entire dust
container.
[0085] The protective shroud 1610 may optionally be formed in a disposable material, and
may then be disposed once, e.g., the Longopac
® bagging system is replaced by a new system. The protective shroud may in such cases
be sold together with the dust container system. The protective shroud 1610 may also
be formed in rubber or a pliable plastic material and can in such cases be integrated
with the hatch mechanism 140, or fixedly attached to the dust extractor.
[0086] To summarize, there is disclosed herein a protective shroud 1610 arranged to at least
partly cover a dust container 810 received in a groove portion 620 of a dust container
holder 180. The protective shroud 1610 is formed in a resilient material allowing
the protective shroud to be folded over the dust container 810 when received in the
groove portion 620.
[0087] According to some aspects, the protective shroud 1610 is formed in rubber or a pliable
plastic material and may also be configured as a disposable unit which is discarded
together with the bagging system. A new protective shroud may then be supplied together
with the bagging system or sold separately.
[0088] The protective shroud 1610 may generally be arranged to envelope a pre-separator
120 of a dust extractor 100 at an end opposite to a dust extractor lid 101, and to
be elastically held in position relative to the pre-separator 120. The protective
shroud may be held in position by traction from its elasticity, or by other means.
[0089] As illustrated in Figure 17, the protective shroud 1610 may be configured with an
annular shape, and with a U-shaped cross-section 1700. Notably, a material thickness
T1 on an outer portion of the protective shroud is smaller than a material thickness
T2 on an inner portion of the protective shroud. I.e., the material thickness of the
protective shroud 1610 is decreasing with radial distance from the center of the annular
member. This makes it easier to fold the protective shroud 1610 over the dust container,
since this folding primarily involves the small thickness portion, and the protective
shroud 1610 is firmly held in position by tractive force due to its elasticity and
increased material thickness T2.
[0090] Figures 9A illustrates an example dust extractor lid portion 101. This lid portion
101 comprises an example valve arrangement 900 for generating pulses of air to clean
an air filter in the pre-separator 120. It is appreciated that the principles of the
valve arrangements discussed herein are applicable in a wide variety of applications,
and not limited to mounting in the exact manner illustrated by the drawings.
[0091] The valve arrangements 900 discussed herein are configured for automatically generating
an air pulse to clean the pre-separator air filter when needed, i.e., when the air
filter is starting to become too particle laden for efficient dust extraction operation.
[0092] Some of the valve arrangements are also possible to operate manually, overriding
the automatic function. Towards this end, a manual control device 910, such as a button
or a knob, is arranged on the lid 101.
[0093] Figure 9B illustrates details of the valve arrangement 900 which will be discussed
in more detail below. Figures 10A-C show example valve arrangements 900 for generating
a pulse of air to clean an air filter 125 of a pre-separator 120. The arrangement
900 comprises a main valve closure body 950 arranged to seal a passage 951 between
a high pressure P2 side and a low pressure P3 side of the valve arrangement 900. The
high pressure side may, e.g., be connected via fluid conduit 901 to atmospheric pressure,
while the low pressure side may be associated with a machine operating pressure, i.e.,
be connected to a point in the dust extraction flow upstream from the air filter 125.
[0094] The valve arrangement 900 also comprises a control body 940 connected to the main
valve closure body 950, such that a position of the main valve closure body 950 is
determined by a position of the control body 940. In other words, if the control body
940 moves, so does the main valve closure body 950. Note that this motion is longitudinal
or normal with respect to a plane of the main valve closure body 950 in Figure 10A,
but this exact configuration is not a necessary feature. The position of the main
valve closure body 950 can be determined by the position of the control body 940 is
many different ways, e.g., via a lever arrangement, via wire, or by some other form
of mechanical linkage.
[0095] The control chamber 930 is partially defined by the control body 940. In the example
of Figures 10A-B, the control chamber is a space which is sealed by a resilient membrane
which is able to move up and down to restrict or expand the volume of the control
chamber. The volume of the control chamber 930 is therefore variable in relation to
the position of the control body 940. Other ways to implement this type of control
chamber would, e.g., comprise a cylinder and piston arrangement, or a balloon arrangement.
If pressure P1 inside the control chamber 930 is smaller than pressure P2 outside
the control chamber, the control body 940 will move due to force F1 to restrict the
volume in the control chamber 930. This motion also pulls the main valve control body
950 into sealing position. Another force F2 acts on the main valve control body 950
due to a pressure difference between the low pressure P3 side and the high pressure
P2 side.
[0096] A control chamber valve 920 having an open state and a closed state for regulating
the pressure P1 in the control chamber is furthermore comprised in the valve arrangement
900. When this valve is opened to increase pressure in the control chamber, e.g.,
from a machine operating pressure to atmospheric pressure, the main valve control
body is shifted into a non-sealing position. The effective area of the control body
940 may be arranged larger than an effective area of the main valve control body 950.
[0097] This general type of control chamber mechanism for opening and closing a main valve
closure body 950 has been proposed previously, see, e.g.,
WO 2017/025305 and
EP3619453 A1. Its basic mechanisms and principles of operation will therefore not be discussed
in more detail herein, although an example will be discussed in connection to Figures
11A-C below.
[0098] Differently from the known valve arrangements, this valve arrangement may be automatically
triggered when the air filter becomes particle laden and is in need of cleaning, or
when the operator blocks the inlet 110. Towards this end, the valve arrangement 900
comprises a resilient trigger membrane 980 arranged between the high pressure P2 side
and the low pressure P3 side such that a position of the resilient trigger membrane
980 is dependent on a pressure difference between the high pressure P2 side and the
low pressure P3 side. The state of the control chamber valve 920 in the valve arrangement
900 is arranged to be determined by the position of the resilient trigger membrane
980 such that the control chamber valve 920 is in the open state when the pressure
difference is above a threshold and in the closed state otherwise.
[0099] Since the membrane is resilient, it will flex and be drawn towards the side of the
membrane with lowest pressure, as illustrated in Figure 10D. Thus, a connecting member
981 attached to the membrane will move in dependence of the pressure difference on
either side of the membrane 980.
[0100] Some optional details of the valve arrangement 900 are illustrated in 10C. Here,
with reference also to Figure 10B, a lever 921 is arranged pivotable about an axis
922 and arranged to connect the resilient trigger membrane 980 to the control chamber
valve 920. Thus, as the pressure difference P2-P3 increases, the resilient trigger
membrane 980 is drawn towards the low-pressure side (pressure P3, downwards in Figure
10C). This motion by the resilient trigger membrane 980 pulls the lever downwards
via the connecting member 981. The downward pulling force F4, when strong enough,
translates into a pivoting motion by the lever 921, causing the control chamber valve
920 to open abruptly.
[0101] An optional biasing member 925, here a leaf spring, is configured to resist this
pivoting motion. This biasing member is part of an optional calibration device 925,
990. Thus, according to some aspects, the valve arrangement 900 further comprises
a calibration device 925, 990 configured to determine the threshold by biasing the
lever to resist pivoting about the axis 922. This calibration device may, e.g., be
a resilient member like the leaf spring shown in Figures 10A and 10C with a tuning
screw 990 to determine the biasing force. A helical spring or other resilient member
can of course also be used for the same biasing effect.
[0102] The lever 921 is optionally arranged to be operable by a manual control device 910
to force the control chamber valve 920 into the open state. This manual control device
910 is exemplified by a push-button directly actuating the lever 921 in Figure 10C.
This manual control device then overrides the automatic triggering function to generate
the pulse of air independently of the pressure difference P2-P3.
[0103] According to other aspects, the control chamber valve 920 and the resilient trigger
membrane 980 are integrally formed. This means that the resilient trigger membrane
980 directly pulls the control chamber valve 920 into the open state as the pressure
difference goes above the threshold, perhaps first overcoming a biasing force exerted
by a resilient member configured to bias the control chamber valve 920 into the closed
position.
[0104] With reference to Figure 10B, the valve arrangement 900 optionally comprises a main
valve biasing member 970 arranged to bias the main valve closure body 950 into sealing
the passage 951. This main valve biasing member can be realized by a helical spring
as shown in Figure 10B.
[0105] Figures 11A-C conceptually illustrate the generation of an air pulse by the valve
arrangements disclosed herein. Figure 11A illustrates an operation state where the
control chamber valve 920 is in closed position, and a low pressure prevails in the
control chamber. This low pressure in the control chamber may be obtained, e.g., by
connecting the control chamber to the low-pressure side of the dust extractor 100.
The main valve closure body 950 is in sealing position due to that the combination
of force F1 generated by the control body 940 and the optional biasing force F3 generated,
e.g., by the resilient element 970 overcomes the force F2 exerted on the main valve
closure body 950 by the pressure difference between the high pressure P2 (normally
atmospheric pressure) and the pressure P3 (the vacuum generated by the blower arrangement
160). Note that the effective area a1 of the control body 940 is larger than the effective
area of the main valve closure body 950. This, for the same pressure difference, when
P1=P3, the force F1 will be larger compared to force F2.
[0106] In Figure 11B, the control chamber valve 920 is opened to increase pressure P1 inside
the control chamber 930, e.g., to atmospheric pressure P1=P2. The force F1 therefore
decreases such that the combination of F1 with F3 no longer overcomes the force F2.
The main valve closure body 950 therefore abruptly leaves the sealing position, whereby
air forcefully enters the pre-separator upstream from the air filter 125. This generates
a pulse of air 1100 which pushes particles away from the exterior filter wall, thereby
cleaning the air filter 125.
[0107] In Figure 11C, the pressure P3 has been increased such that F2 is reduced. The combination
of F1 and F3 now overcomes F2 to once more place the main valve closure body 950 in
sealing position. This process can be repeated until the air filter 125 is not particle
laden anymore.